Evidlo / sph_raytracer

A PyTorch raytracer in spherical coordinates

sph_raytracer

A 3D/4D volume raytracer in spherical coordinates implemented in PyTorch.

Check examples/ for samples demonstrating forward raytracing and retrieval.

Features

• 3D spherical raytracing with optional support for dynamic volume (4D)
• implemented purely in PyTorch for easy integration with PyTorch's optimization and machine learning capabilities
• support for square/circular detectors or other custom detector shapes
• optional retrieval framework for easily defining loss functions and parametric models (currently supports only static 3D volumes)

Quickstart

pip install -e .
python examples/single_vantage.py

python examples/static_retrieval.py

Memory Usage

This library was uses only PyTorch array operations at the expense of memory consumption. The peak memory usage in GB can be approximated with examples/memory_usage.py

>>> %run ~/examples/memory_usage.py

--- Parameters ---

(50, 50, 50) volume
50 observations, 1 channels, (50, 100) sensor

--- Memory Usage ---

Ray coordinates memory: 4.25 GB
Density memory: 0.05 GB

Architecture

Below is a list of modules in this package and their purpose:

Forward Raytracing

• raytracer.py - computation of voxel indices for intersecting rays, raytracing Operator
• geometry.py - viewing geometry (detector) definitions, spherical grid definition

Retrieval

• model.py - parameterized models for representing a density. used in retrieval
• loss.py - some loss functions to be used in retrieval
• retrieval.py - retrieval algorithms
• plotting.py - functions for plotting stacks of images, retrieval losses

Running Tests

pytest sph_raytracer

See Also

tomosipo, which inspired parts of this library's interface.